Domestic Water Purifiers
Various types of domestic water purifiers are available in the market and their cost can range from Rs 1,000 to over Rs 50,000 or more based on the technology used. Apart from ceramic candle-based filters, there are various other categories of water filters/purifiers that incorporate latest technologies of UV (ultraviolet) and R/O (reverse osmosis), whereby a large number of impurities and undesirable minerals, solids and other permanent impurities can be removed, particularly by R/O system.
Conventional non-electric storage water filters/purifiers
These filters employ ceramic candles impregnated with silver to filter and purify the input water. In this method, physical impurities like colour, dirt and micron particles/fibres are effectively filtered, as are residual chlorine and microbes (pathogenic and non-pathogenic). Similarly, other filters/purifiers based on iodine/chemicals technology are equally effective in providing clean and safe drinking water. However, none of these filters are effective in reducing total dissolved solids from the input water. Also, it should be noted that non-electric storage water purifiers require regular maintenance and cleaning of filters clogging of pores due to impurities could slow down the filtration and make it ineffective.
UV-based electricity-operated water purifiers
These are filters that purify the input water through feed-water pressure. Output water can be had when input water has reasonable pressure. They are effective in filtering out physical impurities like colour, dirt and micron particles/fibres as well as residual chlorine and microbes (pathogenic and non-pathogenic). However, this category of purifiers is also not effective in reducing the TDS from input water.
These systems are mainly recommended where the input water is salty and has TDS level beyond 800 mg/l. Based on the technology of forced feed of input water, these purifiers are effective in significantly reducing the TDS level by 80 per cent, which means 80 per cent of the input water is discarded by RO technique. Here, the output water is slightly bitter and one may take time to adjust to the taste. RO systems are more expensive than UV systems and are nearly 10 times the cost of conventional filters.